Date:
2018/06/13
Time:
11:00
Room:
A2 Wivi
Attraction, avoidance or indifference: How fauna respond to edges in fire-prone landscapes
(Oral)
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SEE PEER REVIEW
We know quite a lot about how animals respond to edges in modified and fragmented landscapes, but what do they do in natural systems when edges are created by fire? Are some animals attracted to burnt edges? Or is it safer to avoid them completely?
Edges are ubiquitous, highly influential environmental features. They are ecologically important because they influence a wide range of patterns and processes that affect the distribution and movement of many species. However, we currently know very little about fire as an agent of edge creation, how fire edges change spatially and temporally, or how fauna respond to these landscape features.
This study was conducted in mixed eucalypt forests in South-Eastern Australia. Our primary goal was to quantify how fire edges influence activity patterns of forest-dwelling mammals, and how these patterns change over time. We used a chronosequence of prescribed burns (0-7 years post-fire) and long unburnt control locations (76 years post-fire) to test species response to fire edges over time. We predicted that native mammals, particularly those with behaviors strongly linked to ground level vegetation complexity would indicate activity patterns that closely followed patterns observed in the regenerating vegetation. In contrast, we predicted that the response of feral predators (cats and foxes) would be the opposite, with high activity levels on the burnt edge immediately after fire, as these species commonly prefer open and disturbed habitats.
We used linear mixed models with normal errors when habitat complexity was the response variable being investigated. When animal activity was the response variable we used generalised linear mixed models with binomial errors. We also assessed the congruence between changes in habitat complexity and animal activity across an edge over time, using Vanderploeg and Scavia's Relativised Electivity (Lechowicz 1982).
Habitat complexity was lower on the burnt side of the edge up to two years post-fire, higher in year three, and similar to the unburnt between 6-7 years after fire, indicating rapid vegetation regeneration three years post-fire. Small mammals avoided burnt edges for up to 6 years post-fire, while medium and large mammals either showed no edge effect or were attracted to regenerating burnt edges 1-2 years after fire. Predators were attracted to the burnt edge immediately after fire, with this effect decreasing 1-2 years post-burn.
Earth is intrinsically flammable, with wildfires predicted to increase in extent and severity as a result of climate change. In response to this, prescribed fire is increasingly applied as a management tool globally. Understanding how fire edges alter animal movement patterns over time is important for the conservation of species in fire-prone regions and can lead to improved management of biodiversity in flammable systems.
Reference:
Lechowicz, M.J. (1982) The sampling characteristics of electivity indices. Oecologia, 52, 22-30.